src/bin/lttng-relayd/session.h

   1 #ifndef _SESSION_H
   2 #define _SESSION_H
   3
   4 /*
   5  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   6  *                      David Goulet <dgoulet@efficios.com>
   7  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License, version 2 only, as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  16  * more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along with
  19  * this program; if not, write to the Free Software Foundation, Inc., 51
  20  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include <limits.h>
  24 #include <inttypes.h>
  25 #include <pthread.h>
  26 #include <urcu/list.h>
  27 #include <urcu/ref.h>
  28
  29 #include <lttng/constant.h>
  30 #include <common/hashtable/hashtable.h>
  31
  32 /*
  33  * Represents a session for the relay point of view
  34  */
  35 struct relay_session {
  36         /*
  37          * This session id is generated by the relay daemon to guarantee
  38          * its uniqueness even when serving multiple session daemons.
  39          * It is used to match a set of streams to their session.
  40          */
  41         uint64_t id;
  42         char session_name[LTTNG_NAME_MAX];
  43         char hostname[LTTNG_HOST_NAME_MAX];
  44         uint32_t live_timer;
  45
  46         /* Session in snapshot mode. */
  47         bool snapshot;
  48
  49         /*
  50          * Session has no back reference to its connection because it
  51          * has a life-time that can be longer than the consumer connection's
  52          * life-time; a reference can still be held by the viewer
  53          * connection through the viewer streams.
  54          */
  55
  56         struct urcu_ref ref;
  57         /* session reflock nests inside ctf_trace reflock. */
  58         pthread_mutex_t reflock;
  59
  60         pthread_mutex_t lock;
  61
  62         /* major/minor version used for this session. */
  63         uint32_t major;
  64         uint32_t minor;
  65
  66         bool viewer_attached;
  67         /* Tell if the session connection has been closed on the streaming side. */
  68         bool connection_closed;
  69
  70         /* Contains ctf_trace object of that session indexed by path name. */
  71         struct lttng_ht *ctf_traces_ht;
  72
  73         /*
  74          * This contains streams that are received on that connection.
  75          * It's used to store them until we get the streams sent
  76          * command. When this is received, we remove those streams from
  77          * the list and publish them.
  78          *
  79          * Updates are protected by the recv_list_lock.
  80          * Traversals are protected by RCU.
  81          * recv_list_lock also protects stream_count.
  82          */
  83         struct cds_list_head recv_list; /* RCU list. */
  84         uint32_t stream_count;
  85         pthread_mutex_t recv_list_lock;
  86
  87         /*
  88          * Flag checked and exchanged with uatomic_cmpxchg to tell the
  89          * viewer-side if new streams got added since the last check.
  90          */
  91         unsigned long new_streams;
  92
  93         /*
  94          * Node in the global session hash table.
  95          */
  96         struct lttng_ht_node_u64 session_n;
  97         /*
  98          * Member of the session list in struct relay_viewer_session.
  99          * Updates are protected by the relay_viewer_session
 100          * session_list_lock. Traversals are protected by RCU.
 101          */
 102         struct cds_list_head viewer_session_node;
 103         struct rcu_head rcu_node;       /* For call_rcu teardown. */
 104 };
 105
 106 struct relay_session *session_create(const char *session_name,
 107                 const char *hostname, uint32_t live_timer,
 108                 bool snapshot, uint32_t major, uint32_t minor);
 109 struct relay_session *session_get_by_id(uint64_t id);
 110 bool session_get(struct relay_session *session);
 111 void session_put(struct relay_session *session);
 112
 113 int session_close(struct relay_session *session);
 114 void print_sessions(void);
 115
 116 #endif /* _SESSION_H */